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Serial electrocardiographic changes in idiopathic dilated cardiomyopathy confirmed at necropsy
R L Wilensky1, P Yudelman, A I Cohen
1Department of Medicine, Veterans Administration Medical Center, Washington, DC.
Insights
Idiopathic dilated cardiomyopathy shows progressive electrocardiographic changes, including PR and QRS duration prolongation. QRS amplitudes accurately predict heart weight and left ventricular hypertrophy, outperforming standard criteria.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Diagnostics
Background:
- Idiopathic dilated cardiomyopathy (IDCM) is a significant cause of heart failure.
- Electrocardiography (ECG) is a non-invasive tool for assessing cardiac function.
- Serial ECG changes in IDCM are not fully characterized, and predictive markers for cardiac remodeling are needed.
Purpose of the Study:
- To evaluate serial ECG changes in IDCM.
- To describe a method for predicting heart weight using QRS amplitudes.
- To compare the accuracy of QRS amplitudes versus standard criteria (Estes-Romhilt score) for predicting cardiac hypertrophy.
Main Methods:
- Analysis of serial ECGs from patients with necropsy-proven IDCM.
- Measurement of PR interval, QRS duration, and QRS amplitudes (total 12-lead and V1-V6).
- Correlation of QRS amplitudes with necropsy-determined heart weight and calculated cardiac mass index.
Main Results:
- Progressive prolongation of PR interval and QRS duration observed.
- Conduction abnormalities were present in 82% of patients.
- Total 12-lead and V1-V6 QRS amplitudes showed significant correlation with heart weight and cardiac mass index, outperforming the Estes-Romhilt score.
- Heart weight could be predicted up to 2 years before death using QRS amplitudes.
Conclusions:
- Progressive ECG abnormalities are characteristic of IDCM.
- QRS amplitude criteria provide a more accurate, non-invasive method for predicting left ventricular hypertrophy and heart weight in IDCM compared to traditional methods.
- This method allows for early prediction of cardiac remodeling.
Abstract:
Serial electrocardiographic changes in necropsy-proven idiopathic dilated cardiomyopathy are evaluated and a method of predicting heart weight using QRS amplitudes is described. In 34 patients with multiple electrocardiograms (mean 3/patient) progressive prolongation of PR interval (0.18 +/- 0.03 to 0.21 +/- 0.03, p less than 0.001) and QRS duration (0.10 +/- 0.02 to 0.13 +/- 0.03, p less than 0.0001) was noted. Progressive conduction abnormalities were common (82%). QTc interval and QRS- and T-wave axes did not change. In 50 patients with electrocardiograms within 60 days of death, total 12-lead QRS and V1 through V6 QRS amplitude correlated better with heart weight (r = 0.51, p less than 0.0001 and r = 0.55, p less than 0.0001) than the Estes-Romhilt score did. The mean total 12-lead QRS amplitude was 138 mm with a mean of 106 for V1 through V6. In 31 patients cardiac mass index was calculated and showed significant correlation with 12-lead and V1 through V6 QRS amplitudes (r = 0.68, p less than 0.0001 and r = 0.75, p less than 0.0001, respectively). The QRS amplitudes remained constant during the illness. By using total 12-lead QRS or frontal plane QRS amplitude, heart weight can be predicted as early as 2 years before death. Use of body surface area and QRS amplitude criteria increases the accuracy of heart weight prediction. Thus, progressive electrocardiographic changes are common in patients with idiopathic dilated cardiomyopathy and QRS amplitude criteria are more accurate in the prediction of left ventricular hypertrophy than standard criteria.